The present invention relates to an improved frictionless hydraulic damper and frictionless hydraulic damper-snubber which will remain frictionless during extremely small vibrational movements.
By way of background, in U.S. Pat. Nos. 4,638,895 and 4,768,627 frictionless-hydraulic dampers and frictionless hydraulic damper-snubbers are disclosed. These devices worked well in a majority of applications in which they were used. As stated in these patents, the frictionless performance was due to the use of labyrinth seals or bushings which had a thin film of hydraulic fluid built up between the bushing and the shaft to eliminate metal-to-metal friction as the damper stroked. However, in situations where the vibrations to be damped are about 0.001 inches and smaller in amplitude, there was no thin film of fluid formed between the seal and the shaft so as to produce a hydrodynamic bearing, and thus the parts touched in metal-to-metal contact so that frictionless operation was not achieved. The structure of the present invention overcomes the foregoing deficiency.